Wash. Rev. Code § 36.33.030
An item for said cumulative reserve fund may be included in the county's annual budget or estimate of amounts required to meet public expense for the ensuing year and a tax levy made within the limits and as authorized by law for said item; and said item and levy may be repeated from year to year until, in the judgment of the board of county commissioners of the county the amount required for the specified purpose or purposes has been raised or accumulated. The board of county commissioners may accept gifts or bequests for the cumulative reserve fund and may make transfers from the current expense fund to the cumulative reserve fund. Any moneys in said fund at the end of the fiscal year shall not lapse nor shall the same be a surplus available or which may be used for any other purpose or purposes than those specified, except as herein provided, nor shall moneys in said fund be considered when computing the limitations on cash balances set out in section 4, chapter 164, Laws of 1923 as last amended by section 1, chapter 145, Laws of 1943 and RCW 36.40.090.
RCW 36.33.030